THE DURATION OF ANAESTHESIA PRODUCED IN THE DOG BY THE REPEATED ADMINISTRATION OF DIAL AND NEMBUTAL

¹ From the Department of Medical Research, Banting Institute, University of Toronto, and the Department of Physiology, Queen's University, Kingston, Ontario

Dial was used to produce surgical anaesthesia repeatedly in seven dogs. Three dogs developed a tolerance such that the dose which first produced anaesthesia lasting for at least eight hours, later induced anaesthesia of only an hour or less duration.

Nembutal was used to produce surgical anaesthesia repeatedly in five dogs. The duration of the second anaesthesia might drop as low as one half the initial, but thereafter as many as fifty-three successive injections of the same dose over a period of 83 days produced approximately the same duration of anaesthesia. The duration of anaesthesia was proportional to the dose used.